The invention generally relates to block copolymer membranes. More particularly, the invention relates to zwitterion-functionalized block copolymer membranes.
Porous polymeric membranes, either in hollow fiber or flat sheet configurations may be employed in many applications, such as, hemodialysis, ultrafiltration, nanofiltration, reverse osmosis, gas separation, microfiltration, and pervaporation. For many of these applications, membranes with optimal selectivity as well as chemical, thermal and mechanical stability are desirable. In many applications (for example, bio-separation or water filtration) it may also be desirable to have membranes with one or more of improved hydrophilicity, improved biocompatibility, or low fouling.
Polyarylene ethers, in particular, polyethersulfones and polysulfones are often used as membrane materials because of their mechanical, thermal, and chemical stability. However, these polymers may not have the optimal biocompatibility and hydrophilicity for many applications. Further improvements in membrane hydrophilicity have been achieved by polymer blending, for example, fabricating the porous membrane in the presence of small amounts of hydrophilic polymers such as polyvinylpyrollidone (PVP). However, since PVP is water-soluble it is slowly leached from the porous polymer matrix creating product variability. Alternatively, hydrophilicity has been achieved via functionalization of the polymer backbone and introduction of carboxyl, nitrile or polyethylene glycol functionality, which may also provide chemical resistance and good mechanical properties. However, these chemical modifications may be complicated, expensive and inefficient.
Thus, porous membranes having one or both of optimal hydrophilicity and biocompatibility are desired. Further, polymers capable of being fabricated into hydrophilic porous membranes polymers are also desired.